In recent years, for example, in a memory system, a local area network (LAN) or the like, multivalued PAM-X data (X-ary value) subjected to pulse-amplitude modulation (PAM) is used as data to be serially transmitted. Generally, for example, PAM-4 data of 2-bit (4-ary value) pulse amplitude modulation type is often used.
In a reception circuit or the like which receives serially transmitted PAM-4 data as input data, a clock and data recovery device, which separates and recovers a clock superimposed on a data signal of input data and the PAM-4 data, is used. Hereinafter, the clock and data recovery device may be referred to as a CDR device.